The book has 100,000 charges of combat, after which it degrades to a broken, unusable state. Each book activation will use 200 charges (0.2%) of its total charge, resulting in a maximum of 500 activations. The book can be repaired by 25% by using additional Death notes.

Creating the Book of Death currently costs 33,751,963 coins, and a full recharge (four death notes) costs 7,679,820 coins.

Passive

Book of Death being used to instantly kill a hydrix dragon.

The passive has a 1/30 chance per hit to activate.[1] When it activates, this will instantly kill the monster, or it will deal up to 5,000 damage to bosses. Shattered Worlds' mobs are treated like bosses and will also only receive 5,000 damage.

The book only activates when the target monster still has a high percentage of life points remaining [2] - it won't activate if the monster has already been significantly damaged.